Bioplastics in construction

In Germany, about 13 million tons of plastic are processed annually, over 3 million of which are used in construction. This makes the construction industry the second largest consumer of plastics, after the packaging industry.

Plastics are primarily used in non-load-bearing building components. More than half of this amount is used in pipes and conduits. Other applications include window and door frames, insulation materials, and floor coverings. Plastics also play a significant role in smaller quantities, such as in adhesives, sealants, and coatings.

The most commonly used plastics include:

• Polyethylene (PE): used for pipes and cables
• Polyvinyl chloride (PVC): used for window and door frames
• Polystyrene (PS) and polyurethane (PU), which are mostly used in their expanded form or as a foam for insulation materials

Bioplastics

Bioplastics, also called bio-based plastics, are made from renewable resources such as starch, sugar, cellulose, lignin, or vegetable oils. The first developments in bioplastics date back over 150 years, but they lost importance with the rise of the petroleum industry.

However, new bioplastics have been specifically developed over the past five decades. There are two main groups:

• Chemically novel bioplastics: These have a different chemical structure than their fossil-based counterparts. A well-known example is polylactic acid (PLA).
• Drop-in plastics: They have the same chemical structure as conventional plastics but are made from bio-based materials such as bio-PE (bio-based polyethylene).

It is important to note that: Bioplastics can be both biodegradable and durable. Durable variants are ideal for long-lasting construction products, especially when they are recyclable, as many of these types are. Currently, bioplastics account for only about 1% of the global market. Their main application so far has been in packaging

1 Bioplastics at a glance
2 3D facade made of flax, bioplastics, and corrugated cardboard

Applications in construction

Interest in using bioplastics in construction is steadily growing, though their use is still limited. More and more companies are adding these products to their portfolios. Products already available on the market include:

• Insulation boards made from natural fibers with PLA reinforcement fibers
• Wall anchors made from bio-based polyamide (Bio-PA)
• Floor coverings based on PLA and recycled plastics
• Wood adhesives based on bio-PUR, PLA, and starch-based plastics
• Filler beads made from wood fibers and biodegradable bioplastics for transporting and storing panels

While producing pipes, cables, and window frames from bio-PE, bio-PP, or bio-PVC is technically possible, it is not economically feasible.

The Federal Ministry of Agriculture and Food (BMLEH) is promoting the development of such building products as part of its „Sustainable Renewable Resources“ program. One example: In Chemnitz, an LED-backlit 3D facade made of flax, bioplastics, and corrugated cardboard was installed on the richter & heß VERPACKUNGS-SERVICE GmbH building. Project partners included Chemnitz University of Technology and Fiber-Tech Construction GmbH.

Another area of research funding focuses on developing extruded insulation boards made from bioplastics. The Fraunhofer Institute for Wood Research (WKI) is working on this project, among others.

Bioplastics do not compete with wood and other building materials made from renewable resources. Rather, they complement them, especially for complex geometries or 3D printing. 3D printing is increasingly being used for prototypes, interior design, and temporary structures.

Outlook

As awareness of sustainability grows and environmental regulations become stricter, demand for alternative materials in the construction industry is increasing. Bioplastics offer versatile solutions and help reduce the industry’s ecological footprint.

The following factors are crucial for their long-term success:

• Acceptance within the construction industry
• Development of uniform standards and norms
• Economic scaling of production

The construction industry is transitioning from fossil fuels to renewable resources. Bioplastics will be key to sustainable construction in the future.